The present invention relates to a process for producing plant oleoresin and extracting carotenoids from plant matter.
In recent years the restrictions on the use of solvents in the food industry arc rapidly developing. Many organic solvents which were used in the industry to extract lipophilic substances have fallen under regulatory restrictions which forbid or limit the use thereof. Thus, the use of relatively safe solvents such as ethanol and ethyl acetate is rapidly increasing in the industry. However, these solvents are not strongly lipophilic and therefore are not very efficient in extracting lipophilic substances. This problem has been overcome in several extraction processes by technological and engineering solutions. U.S. Pat. No. 5,837,311 incorporated herein by reference, discloses a process for obtaining tomato oleoresin from fresh tomatoes which have Brix of about 5xc2x0, wherein suitable extracting solvents are selected according to certain solubility parameters.
Other carotenoid extraction processes have been described in the art. U.S. Pat. No. 5,648,564 describes the production of xanthophylls from plant matter. Said patent discloses the extraction of zeaxanthin from Wolfberries. However, the extraction process is carried out on a fraction wherein the Brix is father high, i.e. greater than 10xc2x0 Brix and thus drying is required as an intermediate stage in the process, before the extraction stage.
It has now been found that when plant matter having a Brix greater than 10 is extracted, the subsequent separation of the pulp from the extracting solvent is problematic due to generation of three phases which are difficult to separate, when the plant material before extraction is not dried. The first phase contains solids saturated with solvent, the second phase at the interface between the first and third phase contains polysaccharides, solvent and part of the lipophilic substances, e.g. carotenoids, and the third phase contains the solvent and lipophilic fraction of the plant matter. Obtaining oleoresin from the solids"" phase will provide an oleoresin which contains polysaccharides and other water soluble constituents from the plant matter. This oleoresin is of poor quality, low content of the desired lipophilic substance, i.e. carotenoids and is unsuitable for use for further isolation of the carotenoid contained therein.
In view of the above, there is a long felt need for an economical, efficient process for the separation of carotenoid-containing oleoresin and carotenoids from plant matter of Brix greater than 10xc2x0.
Therefore it is an objective of the present invention to provide an economical, efficient process for the separation of carotenoid-containing oleoresin from plant matter having Brix greater than 10xc2x0.
It is a further objective of the present invention to provide a process for obtaining carotenoids in an essentially pure form from plant matter having Brix greater than 10xc2x0.
Further objectives of the invention will become apparent as the description proceeds.
The present invention provides a process for extracting carotenoids from carotenoid-containing plant matter wherein the Brix in said plant matter is greater than 10xc2x0 Brix, comprising of the following steps:
i. Mixing the plant matter with water to achieve Brix not greater than 10xc2x0.
ii. Crushing the mixture from stage (i) and separating the solids from the liquid to obtain two phases, pulp and serum.
iii. Extracting the pulp to obtain carotenoid-containing plant oleoresin,
Optionally, the process may further comprise a stage of concentrating the serum to obtain a liquid concentrate of the water miscible material of the plant matter.
According to a further aspect of the present invention there is provided a process for the isolation of carotenoids from plant matter wherein the process described above further comprises a stage of isolating the carotenoid from the carotenoid-containing oleoresin obtained in stage (iii) or from the extracts of the extraction stage. Carotenes are isolated from the oleoresin thereof by diluting the oleoresin with a suitable solvent and filtering, to obtain solid carotenoid. Wherein the carotenes are isolated from the extracts, the extracts are diluted with a suitable solvent and filtered to obtain the solid carotene.
According to a further aspect of the invention when the plant oleoresin obtained, contains xanthophylls in the form of an ester or diester, the process further comprises of a stage wherein the oleoresin is subjected to saponification conditions to obtain the fatty-acid-free form of the xanthophylls.